Alarm power supply modules commonly include a built-in charger for sealed lead-acid or gel batteries, allowing the standby battery to remain ready while AC power is available. When AC power fails, the module transfers connected alarm or access control equipment to battery power, while status monitoring can report AC, battery, or charging conditions.

Choose an alarm power supply module with an output voltage that matches the connected equipment, commonly 12 VDC or 24 VDC, and verify whether the devices require individually protected or controlled outputs. Size the current capacity above the combined operating and startup load of the locks, sensors, controllers, and other accessories, while allowing room for battery charging and future expansion.

Fused alarm power supply modules protect each output with a fuse that typically requires replacement after a fault, while PTC-protected modules use resettable overcurrent protection that can return to operation after the fault clears. Both configurations can distribute power to access control devices, with the right choice depending on service preferences, connected loads, and system requirements.

When connecting an alarm power supply module to a fire alarm control panel (FACP), confirm that the module supports the panel’s signaling method, such as a normally open or normally closed trigger, or polarity reversal, and verify whether the installation calls for latching or nonlatching fire alarm disconnect. Also check the module’s output type, protection method, voltage, current capacity, and supervision features so the connected access control devices receive suitable power and can release or disconnect as required during an alarm.